Whip the cream. Whip the cold heavy cream to medium peaks. Refrigerate it while you work on the rest.
1/2 cup cold heavy cream
Beat the cream cheese. In a separate bowl, beat the room-temperature cream cheese with the powdered sugar, vanilla, and salt until completely smooth, about a minute. Scrape down the bowl.
8 oz full-fat cream cheese, room temperature, 45 g powdered sugar, 1 tsp vanilla extract, 1 pinch salt
Warm the peanut butter. Warm the peanut butter in a double boiler until soft and loose — hot-ish, not hot. Natural one-ingredient peanut butter won't fully melt, but you want it warm and soft.
1/2 cup smooth peanut butter
Whisk in the peanut butter. Add the warm peanut butter to the cream cheese and whisk until smooth.
Melt the white chocolate. In the same double boiler, melt the white chocolate. Pull it off the heat when it's about halfway melted and let the residual heat finish it, then whisk it into the cream cheese mixture.
85 g white chocolate
Taste and adjust. Taste the base and add more powdered sugar or salt if needed. It should read a touch too sweet at this stage — the whipped cream will mellow it.
Fold in the cream. Fold the whipped cream into the mixture in 2–3 additions, until smooth and uniform with no white streaks.
Fill the cups. Pipe or spoon the filling into the prepared liners, dividing evenly.
Chill. Refrigerate at least 4 hours, ideally overnight, so the filling sets firm.
Top and serve. Spoon the jelly over each cup and serve.
120 g strawberry or raspberry jelly